The Vortex optical performance is fine for your use. You'll usually be limited by turbulence, so optical performance should be secondary to reticle tracking performance and features. Field reports indicate that turrets on all three scopes track well, IIRC.
I haven't had a SWFA 16X in my hands, so I can't say anything about its optical performance. Again, field reports have been good, IIRC.
I use a fixed 10X for ground squirrels. It works fine. I would not use a fixed 16X if I had other options. Too difficult getting on targets and no option to turn down the magnification when the turbulence (mirage) gets bad. I think you would have regrets with a fixed 16X.